The Speciation of Dean Winchester
by a.lakewood
Summary: Sometimes men can be dogs. Sam and Dean learn that this isn't necessarily a figurative phrase. AU, WINCEST, slight bestiality.


**Title:** The Speciation of Dean Winchester  
**Author:** alakewood  
**Warnings:** AU. Crack-ish. **Wincest. And, um, maybe the slightest little bit of bestiality.** (Nothing _really_ hardcore, but, yeah, I know. *hides face in embarrassment and shame*)  
**Rating:** Hard R (maybe NC-17 to be safe)  
**Word Count:** 4000-ish  
**A/N:** ...Yeah. No idea where this came from. Probably has to do with the fact I've been house-/dog-sitting for a week and a half and the boxer (one of _seven_ dogs I'm watching) has a total Dean temperament. So, yeah – I can honestly say I have _no freaking idea_ what the hell got into me this week.  
**Summary:** Sometimes men can be dogs. Sam and Dean learn that this isn't necessarily a figurative phrase.  
**Disclaimer:** As always, I own nothing.

**oxoxo**

Dean slid onto the stool at the bar beside Sam, his beer bottle catching in a deep chip in the counter top and nearly tipping in his loose grip as his hand moved it on down the bar with him. His knee knocked against Sam's thigh.

"You 'bout ready to get out of here?" Sam asked, picking at the edge of the label on his bottle where the condensation had seeped underneath.

"What's your rush, Sammy?" Dean's knee grazed Sam's thigh again, but it was entirely on purpose this time, steady pressure and the slow friction of denim on denim. "Don't you just wanna let loose? Have a little fun?"

"Uh, not really, no," Sam replied, shifting his legs away from Dean's and smoothing the corner of the label back down.

"Well, I do. So...feel free to hang out here and mope, Mopey." He clapped a hand on Sam's shoulder and climbed back off the bar stool to head over towards the blonde that couldn't have been much more than nineteen that he had been chatting up.

Sam just rolled his eyes as he watched his brother go and finished the last warm swallows of his beer before switching over to water. Dean was drinking enough for the both of them.

**oxo**

Sam had walked himself the two blocks back to their motel, left a horny, grinning Dean behind in the bar parking lot with the blonde draped all over him. Which was why, when the door squeaking open two hours later roused him from a light sleep, he was somewhat surprised. He heard Dean mutter something about 'goddamn crazy-ass kids' before his brother disappeared into the bathroom, then he promptly fell back asleep.

**oxo**

When Sam awoke again, the morning sunlight was beating down on the thin curtains in the one large window at the front of their motel room, making the whole space glow with an orangey-red light. He scrubbed his hands over his face and rolled over with his back to the window and tossed his arm over his eyes. He could hear a padding scuffle across the carpet between his bed and Dean's, not completely awake yet but wondering what the hell his brother was doing up already. Then his mattress jostled and he heard a noise almost like springs squeaking. _Almost_, but breathier and with a whining undertone. It was a _whimper._ Sam rolled over and came face-to-face with a dog.

Well, a boxer to be exact. It whimpered again and let loose a short bark.

Sam quickly sat and moved away from the edge of the bed to press his back against the headboard. "Dean?" he called out tentatively.

The dog's eyes searched his face, ears twitching as a worrisome expression wrinkled his forehead. And again with the whimpering. It reared up on its back legs and put its front paws on Sam's mattress. That was when Sam saw Dean's amulet dangling from its neck.

"Oh shit."

Sam reached a hand for the amulet and the dog - _Dean?_ - hopped back down and made a beeline for the door. He sat there with his head cocked, looking at Sam expectantly.

"You gotta go outside?" Sam asked uncertainly.

The dog – Dean – barked, his docked tail wagging against the worn carpet.

Sam tossed the blankets from his legs, climbed out of bed, and padded over to the door. Dean rubbed his head against Sam's thigh, wet nose poking against Sam's tented crotch as he sniffed. Sam shoved Dean's head away feeling the flush of embarrassment burning color high in his cheeks. "Dude. Seriously."

But even as Sam reached over the dog's head to unlock and open the door, Dean did it again, nose _nuzzling_ against Sam's sac and the underside of his dick. He huffed out a damp breath.

"_Dean!_"

Dean barked in response, eyes wide and innocent, tail wagging even more emphatically.

Sam finally threw the door open and watched Dean race outside, skidding through the patchy grass towards a tree around the corner. All Sam could do as he watched the dog – his _brother_ - lift one of his hind legs to pee at the base of the tree was wonder what the hell kind of trouble Dean had gotten himself into the previous night.

**oxo**

Sam was quick to learn that, as a dog, Dean was much more physically affectionate than he ever was as a person – he needed constant attention and if Sam wasn't touching him, he was whining. He also learned that their fleabag motel had a no-pets policy and he was promptly asked to check out. So Sam was forced to check into a Best Western that allowed him to keep Dean in his room. He knew Dean would bitch about the money it cost once he was human, but, if Dean somehow managed to remember his whole 'my life as a dog' ordeal, Sam doubted he'd have wanted to spend it locked up in a kennel.

Once that was settled, Sam set about getting Dean a proper collar and leash, an errant thought about Dean and kinks making him blush and instantly hard in the empty Wal-Mart aisle. He _knew_ those kinds of thoughts about Dean should be unsettling and disturbing and disgusting, but as they'd grown closer over the past couple of years – especially after their father died – they'd found a lot of comfort in each other's company and Sam could feel their brotherly dynamic shifting into something _else_. Lingering touches and held gazes that they didn't quite acknowledge – like in the bar the night before.

Leaving the aisle, he grabbed a bowl for water, but bypassed the dog food. He could tell Dean was at least somewhat alert inside the dog and that there was no way his brother would eat dog food. Ever.

When he got back out to the car, Dean had managed to get his entire head wedged in the small gap Sam had left at the top of the window. He didn't bark, didn't whine, just panted happily with his tail wagging as soon as he caught sight of Sam. Sam tossed his bag ahead of him into the seat as he climbed into the car and reached over to roll Dean's window down the rest of the way – he received a slobbery lick to his face as a thank-you. He leaned away. "Stop it, Dean. That's disgusting."

He blindly reached for the bag in the passenger's seat between Dean's large paws and pulled the collar from it. There'd been a machine at the end of the aisle that engraved pet tags with names and addresses and phone numbers and Sam had made one for his brother. It was hilarious and a surprising turn-on to know that the tag, once attached to the collar, would make Dean his property. At least temporarily.

Dean eyed him warily as Sam loosened the buckle and fit the two-inch-wide leather collar around Dean's neck and refastened it. "My luck, you're gonna go running off after the first bitch in heat you find and you'll get lost. At least now, if somebody finds you, they've got a number they can call."

Dean stared up at him from the passenger's seat clearly unimpressed and not quite buying whatever bullshit Sam was trying to sell him.

**oxo**

Sam wasn't too far off from the truth when he'd made his 'bitch in heat' comment. He'd tried to leave Dean at the hotel that night before going back to the bar to ask around about the girl Dean had left with, but Dean wasn't having it. Didn't want to be left alone. Kept whining and whimpering and barking until Sam finally put the leash on him and took him along.

Sam had no more than let Dean out of the car a block from the bar before the damn dog took off at a dead run and ripped the leash from Sam's grasp. Sam pursued his brother past the bar and into an alley two blocks down and found him there, crouched low and growling at the darkness, hackles raised in the dim light from the streetlamp just outside the mouth of the alley in front of the crumbling brick building that spanned half the block. "What is it, Dean?" Sam whispered as though Dean might actually be able to reply.

As Sam's eyes adjusted, he could clearly see eight other dogs in the alley, fanned out and blocking them from going any further, as still and unmoving as islands in the middle of the ocean. Dean turned his head ever so slightly towards Sam and gave a couple low barks.

One of the other dogs – what appeared to be a blue tick heeler or some similar kind of hunting dog – barked back at Dean and Sam was almost certain the dogs were communicating somehow. The heeler finally moved, relaxed enough that Dean did too, then turned back towards the other seven dogs of various breeds behind it. It barked a couple of times and the dogs scattered. Sam watched with fascination as Dean approached it, barks and yips and whines substituting for words as the two stood a couple feet apart, their gazes occasionally wandering back to Sam. A couple of times, Dean made to move towards the alley exit, but the heeler would bark sharply and give a slight shake of his head. After a good ten minutes of their back and forth, Dean was finally allowed to leave, Sam following behind because there wasn't much else he could do.

**oxo**

Dean had slowly walked with Sam back towards the bar but kept walking past it to sit impatiently beside the Impala as he waited for Sam to catch up. It was apparent from Dean's demeanor that they wouldn't be looking for Dean's conquest, so Sam let Dean into the car and rounded to the driver's side to let himself in as well. The ride back to the hotel was quiet and Dean just sat sullenly on the seat, staring out the window. Sam reached over and scratched behind one of Dean's ears. "What's going on, man? You okay?"

Dean's head tilted sideways as he stared at Sam, then he turned around and flopped down onto the seat for the remainder of the drive with his head resting heavily on Sam's thigh. He sighed contentedly.

**oxo**

Sam awoke the following morning to pressure and heat between his legs, damp friction that made him drop his knees to the sides and arch his hips off the bed in sleepy need. He reached between his legs to give himself a good stroke, his hand coming into contact with soft short fur. Any lingering sleepiness quickly disappeared as he realized _Dean_ was between his splayed legs, nose prodding, flat tongue licking slow stripes along Sam's cotton-covered dick. "What the fuck, Dean?"

Dean immediately backed off, whimpering quietly, and folded himself up on the corner of the bed furthest from Sam.

"You gotta stop doing that, okay?" He pulled the bedcovers over his lap and muttered to himself, "Jesus _Christ._"

He felt like such a freak, even closer to coming than he had been _before_ he woke up completely. He tossed the blankets from his lap over Dean and made a beeline for the bathroom, hearing Dean whine as he tried to get out from underneath the comforter.

Sam emerged twenty minutes later in a towel, cleaner and more clear-headed, and pulled clothes from his duffel on the table. He looked pointedly at Dean. "I'm gonna find that chick you left the bar with – I think she's got something to do with your...problem."

Dean barked at him, tail wagging, as though he were agreeing.

"So, it's the girl then?"

Another enthusiastic bark.

"And she'll be back tonight?"

Dean offered a hesitant woof before climbing off the bed and loping over to the door.

"Yeah, yeah," Sam said. "Let me get dressed."

**oxo**

Sure enough, when Sam entered the bar later that night, the girl that Dean had been with was already there, already had some helpless guy wrapped around her little finger and buying her drinks. Sam pushed his way through the people standing at the bar to stand beside her. He flagged the bartender down with a twenty and turned to the girl. "Hey," he said, getting her attention. "You were in here on Thursday, weren't you?"

The girl eyed the young executive-looking guy that had been buying her drinks, then turned to look at Sam. Her excessively white smile widened as her gaze swept up and down Sam's body. She pressed closer to him, ignoring the protests of Mr. Junior-VP-Assistant or whatever, as she purred, "Mmhmm."

"I thought I recognized you." He offered her his most dazzling smile, hoping it didn't look as forced as it felt.

"It's funny," she said, "'cause I'm really good with faces but I don't remember you. And I'd _remember_ you."

Sam took a swig of the beer that was set before him. "Yeah. You were with some other guy."

She wrinkled her nose as she looked up at him from under her heavily mascaraed eyelashes. "That was nothing. Guy was a total dog. Just wanted a one-night stand. I'm not that kind of girl."

"No," Sam said, knowing for certain that she was responsible for his brother's condition, "you don't seem like the type at all."

She flipped her blonde hair over her shoulder and offered her hand. "I'm Kendra."

He took her hand and lightly shook it. "Sam."

**oxo**

They talked for a while, Sam slowly nursing his beer. When it was finally gone, he set his empty bottle in the groove at the edge of the bar and turned back towards Kendra. "The whole bar thing really isn't my scene," he told her. "Do you maybe want to go get a cup of coffee or something?"

She beamed up at him. "Sure. Why don't you come over to my place? We can talk some more."

Sam nodded, returning her smile. "Yeah, okay. I'd like that," he told her. When, in reality, he'd rather be back in a no-star motel on a two-lane highway just outside some armpit of a town finishing off a six-pack and a bottle of cheap liquor with his brother. But he had to figure out what she'd done to his brother and how to fix it before he and Dean could have any semblance of what passed for _their_ normal lives back.

**oxo**

Sam followed Kendra over to her place and parked halfway down the block, Dean protesting in quiet whines as Sam shut the door in his face. "I'll be back in a little bit, Dean. Don't worry."

But Dean pressed his nose to the glass and snorted, steaming up the window then promptly licking it clean.

Sam was thankful that there was no parking in front the house Kendra had led him to. He doubted she'd forgotten what the car looked like even if she didn't remember seeing Sam at all. He strode down the sidewalk towards where Kendra was waiting and joined her in front of what he guess was a duplex. The house – which appeared to be about the standard size for most houses in small towns – had two separate entrances with two different mailboxes. He wondered if Kendra's neighbor had any idea who or what she really was.

She led him inside and gave him a brief tour, stopping in the kitchen where she put a pot of coffee on. She gestured to the small table and they sat. "So..." she began, looking at Sam demurely from under her lashes again.

"So..." Sam echoed. He couldn't wait anymore, couldn't keep up the charade when he knew with _every fiber of his being_ that Kendra had been the one to turn Dean into a dog. "So what happened to that guy you brought back here on Thursday?"

Kendra made a face. "I don't know. I don't want to talk about him."

"See, that guy? He's my brother. And he's a _dog_ now, thanks to you."

Her eyes widened just enough that Sam knew she knew she'd been caught, but she played dumb anyway. "What? That's _crazy._ Sam, I...I think you should leave." She schooled her expression into one of barely-controlled fear and Sam hoped at least a little of that was real.

"Not until you turn him back."

"Turn him back...I don't- You need to go, Sam. Now."

"I'm not leaving."

Kendra stood and Sam stood too, loomed over her like a mountain over a valley and just as menacing. "You. Are. Crazy," she told him slowly.

"What are you? A witch? Or are you just one of those kinds of girls that likes to dabble in a little of the black arts?"

The mask of fear slid from her face, only to reveal one of boredom beneath it. "I'm not trained, if that's what you're asking. Started coming into my powers and I've been practicing on my own. What are you?"

"A hunter."

"A _hunter_? Whoop-de-frickin'-do. Now you've got a little hunting buddy."

Sam scoffed. "Not that kind of hunter. See, people like me routinely kill people like you. Sure, if you're harmless, I'll leave you alone – but the fact that my brother is currently a different _species_ says otherwise. Change him back now or I'll just kill you and find somebody who can."

There was genuine fear in Kendra's eyes then. "Look, he brought it on himself," she rationalized to Sam. "The way he was all over me and had only one thing on his mind. I'm not a piece of meat for guys to drool over."

"Then maybe you shouldn't dress like one." He followed her out of the tiny kitchen and into her bedroom, off of which there was a crawlspace. "I'm gonna warn you right now that I'm wearing a couple different wards and any kind of magic you try to throw at me is only gonna hit you threefold. So just fix my brother and any other sorry son's of bitches you whammied."

Kendra shook her head piteously and disappeared into the small room, reappearing a couple moments later with one of Dean's leather bracelets and a handful of other small, miscellaneous objects. "There. They'll all be fine. Just a quick nap and they'll be men again." She made a face at Sam and shook her head again. "At least, maybe now they'll all respect women a little more."

**oxo**

When Sam returned to the Impala, Dean was asleep stretched out on the front seat. Dean. Not Dean-as-a-dog, but _Dean_. Completely naked except for the collar Sam had bought for him. Sam grinned and tapped on the window causing Dean to immediately bolt upright. Wild eyes turned to Sam and Dean's chest rose and fell quickly with shallow breaths.

"Sam-" Dean stopped, instantly realizing he wasn't _barking._ He glanced down at his body and didn't seem the least bit concerned with his nudity. "Sammy! I'm not a dog anymore!"

Sam rounded the Impala and pulled a pair of jeans out of the bag of dirty laundry in the trunk for his brother. He opened his door and tossed the pants at Dean. "Yeah. Now you're a _real_ boy."

Dean slipped into his jeans and settled back into his seat. "Wait 'til we get back to the hotel and I'll _really_ show you how real I am."

**oxo**

Dean had Sam shoved up against the door to their room as soon as they were inside, lining their bodies up from chest to thigh and pressing as close as the physical properties of matter would allow him. "I've been wanting this for so long," Dean breathed against Sam's neck before his teeth scraped and bit, canines dragging along suddenly hypersensitive flesh and over Sam's jaw to his mouth where Dean's tongue plunged past his lips with a primal hunger.

By then, Dean was too distracted to notice that Sam had slipped his finger into the O-ring in Dean's leather collar and gave his brother a sharp tug away from him. Dean's lip curled and his nostrils flared, but he didn't argue. If anything, it made the arousal in his eyes burn hotter. Sam groped along the table for the leash and attached it to the collar, pulling Dean along after him towards the bed. "Come," Sam ordered, only feeling slightly silly.

Dean did as he was told and followed Sam to the bed and they both quickly stripped.

"Turn around."

Dean obeyed, felt Sam pull the leash taut as he reached for one wrist and then the other, bound them behind his back. "You're a kinky bastard," Dean laughed.

"Takes one to know one." He turned Dean around and shoved his brother down onto the mattress, helped him get back up on his knees with his face buried in the blankets.

Dean let loose a familiar whimper as Sam's spit-slick thumb stroked over his puckered hole and he pressed back against it. "Come on, Sammy, no need to be gentle here."

"I don't want to hurt you."

"Well _I_ want you to. God, Sam, wanted this for so long just want to _feel_ you."

So Sam lined his dick up with Dean's hole and started to press forward, ignoring Dean's quick breath sucked in through clenched teeth, but he couldn't ignore the painful tightness of his brother's ass. "You're too tight," Sam said. "And there's too much friction. We need lube. Or more time for me to work you open."

"You seem pretty knowledgeable about gay sex. Anything you want to tell me, Sammy?" Dean questioned, face still press to the mattress.

"It's not all that difficult to figure out, dumbass." Sam sucked his thumb back into his mouth before setting about working his brother open. There might've been some lube in the car, but there was no way he was leaving the hotel room yet – not when his morals or sanity could start creeping in to make him doubt the rightness of what he was feeling with Dean writhing beneath him.

Dean's body was loosening around Sam's thumb so he replaced it with two of his fingers, letting them penetrate deeper and scissor this way and that, stroking Dean's prostate and earning him a stuttered breath of, "Fuck _yeah._"

And it wasn't long before Sam was able to try again, pressing the head of his dick against his brother's opening and pushing in, still meeting resistance, but nothing like before. It wasn't until he really started moving that- "Holy fuck, Dean, you're so...God, you're so fucking _tight._"

Dean just barked out a laugh at Sam's awe. "You being hung like a freaking Great Dane has a lot to do with it."

Sam started to laugh too, but it was aborted when the muscles inside Dean's suddenly clenched around him and he was coming, everything going bright and dark at the same time. He collapsed onto Dean's back, his brother's bound hands wedged between them and he gave a tug to the leash, forcing Dean to tilt his head back. It granted Sam access to his brother's throat and Sam went to work sucking a biting the skin on either side of the leather collar as his hand found its way down to Dean's hard dick. Keeping a firm hold on the leash, he set about making his brother come.

It didn't take long before Dean was shuddering next to Sam, wet heat spilling over Sam's fingers, Dean's thigh, and the bedspread. "That was...Fuck, that was good."

"Mm," Sam agreed, fully sated, as he slowly unwound the leash from Dean's raw wrists.

Dean rolled over and pressed his body against Sam's. He tilted his neck to the side, exposing the bruising flesh to Sam as an offering. Sam tongued along the leather, laving over angry red marks, trailing his lips up Dean's throat to his mouth. Dean chuckled, Sam swallowing the sound.

"What?"

"Just thinking...it's a good thing she didn't think men were pigs, huh?"


End file.
